Fiber coating processing and slitting for non-confined light leakage

ABSTRACT

An optical fiber and methods of processing and manufacturing an optical fiber comprising a core, a cladding and a coating covering a segment of the cladding proximate to an end of the optical fiber are presented where patterned apertures are provided in the coating such that a portion of light propagating in the cladding escapes through the patterned apertures of the coating. The patterned apertures allow non-confined light to escape from the cladding in the coating region to provide reduced absorption of the non-confined light by the coating.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Divisional of application Ser. No. 11/228,368,filed Sep. 16, 2005, the entire contents of which are hereinincorporated by reference.

FIELD OF THE INVENTION

The present invention concerns optical fibers, particularly a method forremoving excess power from a coated fiber end and an aperture patternedcoated fiber optical fiber end.

BACKGROUND OF THE INVENTION

An optical fiber is typically attached in at least two places withinoptical packages. An endface of an optical fiber is typically attachedin front of an optical device emitting light, such as a diode laser. Theoptical fiber may also be held in place at a feedthrough point in theoptical package, so that the package may be sealed and prevent againstatmospheric leakage into and out of the package. The optical fiber endwithin the optical package is typically metallized for attachment andsealing of the optical package. The end of an optical fiber is typicallysoldered in place so that it may be precisely aligned with a diode laserand held in this position for a number of years.

Optical packages vary and thus attachment points For an optical fibermay vary with an optical package. Metallization is typically provided toa significant portion of the optical fiber end in the manufacturingprocess. In terms of manufacturing, this allows for use of the sameoptical fiber with different optical packages and/or light sources.Thus, the optical fiber may be soldered at any position along themetallization depending at least on the optical package.

SUMMARY OF THE INVENTION

The present invention is embodied in an optical fiber comprising a corehaving a first index of refraction, a cladding surrounding the core andhaving an index of refraction less than the index of refraction of thecore and a coating covering the cladding. The coating is located in asegment proximate to an end of the optical fiber and has patternedapertures such that a portion of light propagating into the claddingescapes through the patterned apertures of the coating. The patternedapertures tend to reduce absorption of the portion of light by thecoating.

The present invention is also embodied in an optical fiber for receivinglight from a source of light. The optical fiber comprises a core forreceiving light from the source of light and having a first index ofrefraction and a cladding surrounding the core having an index ofrefraction less than the index of refraction of t:he core. The opticalfiber further comprises a coating covering the cladding in a segmentproximate to an end of the fiber and having patterned apertures. The endof the optical fiber has an edge adjacent to the source of light and thepatterned apertures are configured to allow a portion of the light toescape through the coating such that reduced absorption of the portionof light occurs in the coating.

The present invention is further embodied in a method of processing anoptical fiber comprising a core having a refractive index, a claddingsurrounding the core having an index of refraction less than the indexof refraction of the core and a coating on the surface of a segment ofthe cladding, the segment proximate to an end of the optical fiber. Themethod selectively removes portions of the coating to provide patternedapertures in the coating.

The present invention is further embodied in a method of manufacturingan optical fiber. The method comprising the steps of providing a corehaving a refractive index and forming a cladding surrounding the corehaving an index of refraction less than the index of refraction of thecore. The method further comprising applying an aperture patternedcoating to a surface of a segment of the cladding proximate an end ofthe optical fiber.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed descriptionwhen read in connection with the accompanying drawing. It is emphasizedthat, according to common practice, the various features of the drawingare not to scale. On the contrary, the dimensions of the variousfeatures are arbitrarily expanded or reduced for clarity. Included inthe drawing are the following figures:

FIG. 1 a (Prior Art) is a side view of a lensed tip metallized opticalfiber end portion with a fiber buffer for coupling within an opticalpackage;

FIG. 1 b (Prior Art) is a side view of a flat tip metallized opticalfiber end portion for coupling within an optical package;

FIG. 1 c (Prior Art) is a side view of a lensed tip partially metallizedoptical fiber end portion for coupling within an optical package;

FIG. 1 d (Prior Art) is a side view of a second lensed tip partiallymetallized optical fiber end portion for coupling within an opticalpackage;

FIG. 2 a (Prior Art) illustrates the relationship between fast axispower of a diode laser and transfer of the power into a multimodeoptical fiber end;

FIG. 2 b (Prior Art) illustrates the relationship between slow axispower of a diode laser and transfer of the power into a multimodeoptical fiber end;

FIG. 3 a is a side view illustrating damage to a coated fiber bufferalong a conventional multimode coated optical fiber end due to absorbednon-confined light;

FIG. 3 b is a side view illustrating damage to an end section of coatingalong a conventional multimode coating optical fiber end due to absorbednon-confined light;

FIG. 3 c is a side view illustrating damage to a portion of coatingalong a conventional multimode coated optical fiber end due to absorbednon-confined light;

FIGS. 4 a is a side view of a first exemplary aperture patterned coatedoptical fiber end according to the present invention;

FIG. 4 b is a side view of a second exemplary aperture patterned coatedoptical fiber end according to the present invention;

FIG. 4 c is a side view of a third exemplary aperture patterned coatedoptical fiber end according to the present invention;

FIG. 4 d is a section view of the third exemplary aperture patternedcoated optical fiber end according to the present invention;

FIG. 4 e is a side view of a fourth exemplary aperture patterned coatedoptical fiber end according to the present invention;

FIG. 5 is a flowchart illustrating an exemplary method ofpost-processing a coated fiber to provide an aperture patterned coatedoptical fiber, according to the present invention;

FIG. 6 is a flowchart illustrating an exemplary method of aperturepatterned coated optical fiber manufacture, according to the presentinvention; and

FIG. 7 is a flowchart illustrating an alternate exemplary method ofaperture patterned coated optical fiber manufacture, according to thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawing, in which like reference numbers refer tolike elements throughout the various figures that comprise the drawing,FIGS. 1 a-d show examples of metallized optical fiber ends according tothe prior art. An optical fiber 102 may have an end 104 that istypically metallized 108 for placement within an optical package (notshown) for alignment with, for example, a diode later (not shown).

FIG. 1 a illustrates a known in the art optical fiber 102 where end 104is metallized 108 to a lensed tip 106. Lensed tip 106 may be lensed forfocusing optical power from a diode laser as described below. Opticalfiber 102 may also include a fiber buffer 110 between fiber end 104 andthe remaining length of optical fiber 102.

FIG. 1 b illustrates another common in the art optical fiber end 104′. Aknown in the art flat tip 112 may be used with metallization 108 appliedthe length of optical fiber end 104′ to flat tip 112.

FIGS. 1 c and 1 d illustrate two common in the art optical fiber ends104″ and 104′″, respectively. In these examples, metallization 108 doesriot extend along the length of the optical fiber ends 104″ and 104′″.FIGS. 1 c and 1 d illustrate different places for exposing the barecladding 114. In both of these examples a lensed tip 106 is illustrated.

For all optical fiber ends, the optical fiber may be metallized 108 inat least two places within an optical package (not shown). The firstlocation being where the optical fiber end is attached to be alignedwith a diode laser (not shown). The second location may be at afeedthrough point of an optical package (not shown) to seal the opticalpackage.

Typically, it is more efficient to metallized the entire optical fiberend as shown by ends 104 and 104′ in FIGS. 1 a and 1 b. Partialmetallization which exposes the bare cladding 114 as shown in FIGS. 1 cand 1 d may require a further processing step. This processing step mayvary by, for example, the optical package, the optical source and theapplication and may not be efficient for manufacturing purposes.

Although FIGS. 1 a-d illustrate an optical fiber having a metal coating,it is understood that the present invention may be practiced with anyoptical fiber having a coating such that absorbed non-confined light maydamage the coating. For example, the coating may be acrylate, polyimideor carbon.

Although FIG. 1 a illustrates a lensed tip 106 and a fiber buffer 110and FIG. 1 b illustrates a flat tip 112, it is to be understood that anoptical fiber end may use any tip, including at least lensed and flat.The type and shape of a tip may depend on the optical sourcerequirements and the application. Optical source requirements mayinclude the type of optical source, such as a diode laser, the opticalpower of the optical source and an optical brightness. The opticalbrightness may further depend on the numerical aperture (NA) of theoptical fiber. A fiber buffer may be used with any optical fiber.

A typical optical source is a diode laser. A diode laser typicallyincludes confined and non-confined light. For example, a diode laser mayhave fast axis and slow axis power. In general, fast axis and slow axispower correspond to confined and non-confined light, respectively. Anoptical fiber tip may be lensed to improve the coupling of fast axispower from a diode laser to a multimode optical fiber. Even withlensing, however, some of the fast axis power may not be confined to thecore of the optical fiber. In addition, slow axis power is typically notconfined to the core and may also extend into the cladding.

Referring now to FIGS. 2 a and 2 b, an example of coupling of fast axisand slow axis power, respectively, between a diode laser and aconventional multimode optical fiber is now described. A multimodeoptical fiber core 202 and cladding 204 are illustrated in FIGS. 2 a and2 b. Although the example illustrates fast and slow axis power, it isunderstood that the relationship may be extended to any non-confinedlight situation.

FIG. 2 a illustrates the fast axis power 208 from a diode laser inrelationship to core 202 and cladding 204. It is assumed that theoptical fiber is properly aligned with the diode laser. Lines 206represent the acceptance cone of the fiber. The fast axis power istypically Gaussian-shaped. For the fast axis, the majority of the power208 is desirably within core 202. Only a small portion of the power atlow amplitude escapes into the cladding. Thus the fast axis powertypically does not propagate significantly in cladding 204.

FIG. 2 b illustrates the slow axis power 210 from a (diode laser inrelationship to core 202 and cladding 204. It is assumed that theoptical fiber is properly aligned with the diode laser. Lines 206represent the acceptance cone of the fiber. For a multimode diode laser,the slow axis is typically the summation of a number of single-modeGaussian power curves. Thus the slow axis power is typically asrepresented by curve 210. For the slow axis power, the majority of thepower 208 typically occurs within core 202 and extends outsideacceptance cone 206 into cladding 204. The slow axis power 210 thatextends to cladding 204 may also be at a high power amplitude. Thus, theslow axis power 210 may not be confined to core 202 and may be coupledto or propagate through the cladding 204.

The non-confined light may propagate through cladding 204 as a claddingmode or may attempt to exit the cladding. However, at the fiber, end,the cladding is coated (not shown in FIGS. 2 a and 2 b) and non-confinedlight that attempts to exit through the coating may cause localizedheating due to absorption at the cladding-coating interface. Thenon-confined light may also be absorbed in a buffer region away from thecoated optical fiber end as the non-confined light travels down thelength of the optical fiber.

In general, confined light may be any light that is reflected orrefracted within the fiber core. Non-confined light may either beabsorbed at the cladding-coating interface or may escape through thecoating. It is desirable to prevent absorption of the non-confined lightat the cladding-coating interface.

Referring now to FIGS. 3 a-c, damage along a coated optical fiber end ofa conventional optical fiber caused by absorbed non-confined light isdescribed. The inventors have determined that as the diode laser powerincrease(s or in high brightness situations the absorbed non-confinedlight may prove detrimental and cause damage to a conventional opticalfiber coating. FIG. 3 a illustrates damage 302 in a fiber buffer 110region. FIG. 3 b illustrates a conventional optical fiber end 104″having coating 108 removed to expose bare cladding 114. In this example,absorption damage 304 is shown in an end region of coating 108 of end104″. Hot spots caused by the absorbed non-confined light and thuspotential damage may occur along any region of the fiber end, asillustrated in FIG. 3 c with damage to coating 306.

Although the figures illustrate a region of fiber coating damage,multiple regions may occur both within fiber end 104 and fiber bufferregion 110. Although a lensed tip 106 is shown, it is to be understoodthat fiber coating damage may occur with other types and shapes of fibertips and coated fibers where the optical power is allowed to benon-confined to a multimode optical fiber core.

Exemplary optical fibers may have a 105 μm core and a 125 μm cladding.Exemplary optical fibers may further have a NA between 0.15 and 0.22.The inventors have determined that continuous wave (CW) diode laserpower above 1 W in 0.15 NA multimode optical fiber may lead to localizedhot spots. High optical power in excess of about 4 W from a singleemitter may cause damage to an optical fiber coating.

In addition to high optical power, damage may also depend on opticalbrightness. For example, an optical fiber with a smaller NA may providemore problems with hot spots due to increased brightness compared with alarger NA. This in turn may lead to fiber, coating or epoxy (buffermaterial proximate to the optical fiber end) damage due to laser powerabsorption. It may also eventually cause catastrophic optical packagefailure. Such damage may initially start with discoloration of thesecoated portion of the fiber or the buffer material such as acrylate.However, the damage may then rapidly degrade the optical fiber and causefiber breakage or bending that result in low output power and failure ofthe entire optical package.

There is also a relationship between the optical power and NA(brightness). As the drive current of the optical source increases andoptical Flower increases, both the confined and non-confined opticalpower change. The non-confined optical power may start to fall outsideof the acceptance cone of the fiber 206 (NA of core) and become coupledinto the cladding with a smaller NA before occurring with a larger NA.Thus, a smaller NA may result in hot spots and potential fiber damage ata lower optical power than for a larger NA.

Within a typical optical package, the coated optical fiber is typicallyattached with solder at the two attachment points. These points may be afew millimeters apart. At the solder attachment points, the solder maybe connected to a tease of the optical package. Any heat that may becaused by the absorbed non-confined light in the cladding may be leakedout of through the solder connected to the base. Between the solderattachment points, the coating is typically very thin. The coating maynot be able to propagate the heat build up and may thus lead to fiberdamage between the solder connection points. It is understood that thecoated optical fiber may be attached to the optical package at oneattachment point or more than two attachment points.

Referring now to FIGS. 4 a-e, embodiments of the present invention aredescribed. To reduce optical fiber damage, an aperture patterned coatingmay desirably be provided to an end of optical fiber 402. According toan exemplary embodiment of the present invention, apertures arranged ina pattern may desirably be provided in the coating to allow non-confinedlight typically absorbed to escape Through the apertures in the coating.Reduced absorption of the non-confined light is desirably provided andhot spots and thus damage to the optical fiber may be avoided.

FIG. 4 a illustrates an exemplary embodiment of the present inventionwith an aperture patterned coating 408 provided along the length ofoptical fiber end 404 of optical fiber 402. The aperture patternedcoating 408 of the exemplary embodiment is desirably a removal of thecoating in a helix along the length of the fiber end 404.

It is to be understood that an exemplary embodiment of the presentinvention may also include a removal of the coating in a plurality ofgrooves at an angle relative to the length of optical fiber 402. It isto be further understood that each groove may or not extend completelyaround the circumference of the fiber end 404. For example, the coatingmay be removed with a laser after placement of the optical fiber end 404in an optical package (not shown). A laser may not be able to remove thecoating underneath the optical fiber end 404. It is contemplated that alaser may remove the coating underneath the optical fiber by ablatingthe coating through the optical fiber. Thus the grooves of aperturepatterned coating 408 may or may not continue along the bottom ofoptical fiber end 404.

In this embodiment a lensed tip 406 and fiber buffer 410 are shown. Itis understood that aperture patterned coating 408 may be applied to anytype of multimode fiber where absorption of non-confined light may causefiber damage. Aperture patterned coating 408 may be applied to a portionof fiber end 404. Optical fiber 402 may have a lensed tip 406, flat tip414 as shown in FIG. 4b or any other type of tip as determined by atleast an optical source, an optical fiber, an optical package, anapplication or any combination therein. Additionally, optical fiber 402may not have a fiber buffer 410 as shown in the further embodiments ofFIGS. 4 b-c.

FIG. 4 b illustrates a second exemplary embodiment of the presentinvention with aperture patterned coating 412 provided along the lengthof optical fiber end 404′ of optical fiber 402. Aperture patternedcoating 408 of the exemplary embodiment is a removal of the coating in aplurality of circumferential grooves along the length of the fiber end404. In this second exemplary embodiment, patterned coating 412 arearranged in grooves that are normal to the length of the optical fiber402.

It is to be understood that each groove may not extend completely aroundthe circumference of the fiber end 404′. As described above, the coatingmay be removed after placement of the optical fiber end 404′ in anoptical package (not shown). Thus the grooves of aperture patternedcoating 412 may or may not continue along the bottom of optical fiberend 404′.

In this second exemplary embodiment a flat tip 414 is shown. It isunderstood that aperture patterned coating 412 may be applied to anytype of multimode fiber where non-containment of optical power may causefiber damage. Aperture patterned coating 412 may be applied to only aportion of fiber end 404′. The second exemplary embodiment may furtherinclude a fiber buffer 410. The second exemplary embodiment may bepracticed with other types of tips including lensed tip 406, asdetermined by at least an optical source, an optical fiber, an opticalpackage, an application or any combination therein.

FIG. 4 c illustrates a third exemplary embodiment of the presentinvention with aperture patterned coating 416 provided along a portionof optical fiber end 404″ of optical fiber 402. Aperture patternedcoating 416 of the third exemplary embodiment is a removal of thecoating in a plurality of polygon or oval shaped apertures along aportion of fiber end 404″.

The plurality of apertures of aperture patterned coating 416 areillustrated as regularly spaced circular apertures. It is to beunderstood that the apertures may be of any polygon shape, and that theymay further be randomly spaced.

FIG. 4 d illustrates a section view of the third exemplary embodiment ofthe present invention. A portion of aperture patterned coating 416 ofoptical fiber 402 surrounds cladding 418. Apertures 420 are provided inthe coating to expose cladding 418. Apertures 420 are illustrated asoval shaped with random spacing. However, apertures 420 may be of anyshape and may further be regularly spaced.

It is to be understood that apertures provided in the coating may notextend completely around the circumference of the fiber end 404″. Asdescribed above, the coating may be removed after placement of theoptical fiber end 404″ in an optical package (not shown). Thus theapertures may or may not be provided along the bottom of optical fiberend 404″.

In the third exemplary embodiment illustrated in FIG. 4 c, a portion 418of the optical fiber end 404″ is bare cladding. It is to be understoodthat the coating may extend the length of the optical fiber end 404″. Itis further understood that the aperture patterned coating 416 may beapplied to any type of multimode fiber where non-containment of opticalpower may cause fiber damage. The third exemplary embodiment may furtherinclude a fiber buffer 410. Although the third embodiment is shown witha lensed tip 406, the invention may be practiced with other types oftips including flat tip 414, or any other type of tip as determined byat least an optical source, an optical fiber, an optical package, anapplication or any combination therein.

FIG. 4 e illustrates a fourth exemplary embodiment of the presentinvention with a two different aperture patterned coatings 416 and 422provided along portions of optical fiber end 404′″, of optical fiber402. Aperture patterned (coating 416 is described above. Aperturepatterned coating 422 of the fourth exemplary embodiment is anotherexample of removal of the coating in a plurality of polygon shapedapertures along a portion of fiber end 404′″ according to a regularpattern.

The plurality of apertures of aperture patterned coating 422 areillustrated as regularly spaced square apertures arranged in acheckerboard pattern. It is to be understood that the apertures may beof any polygon shape. Although the fourth exemplary embodimentillustrates two types of polygon shaped aperture patterns, it isunderstood that a combination of grooves as shown in FIGS. 4 a and 4 band polygons as shown in FIGS. 4 c and 4 e may be provided according tothe present invention.

Although FIG. 4 e illustrates two regions of aperture patterned coatingsand two regions of bare cladding 418, it is understood that any numberof aperture patterned coating regions and bare cladding regions may bepresent, provided that there is coating in locations for attaching theoptical fiber end 404′″ to an optical package as discussed above. It isfurther understood that any number of types of aperture patterned coatedareas may be combined without separation by bare cladding 418.

It is to be understood that the polygon shaped apertures provided in thecoating may not extend completely around the circumference of the fiberend 404′″. As described above, the coating may be removed afterplacement of the optical fiber end 404′″ in an optical package (notshown). Thus the polygon shaped apertures may or may not be providedalong the bottom of optical fiber end 404′.

In the fourth exemplary embodiment illustrated in FIG. 4 e, multipleportions 418 along optical fiber end 404″ are bare cladding. It is to beunderstood that the coating may extend the length of the optical fiberend 404′″. It is further understood that the patterned coating 416 maybe applied to any type of multimode fiber where non-containment ofoptical power may cause fiber damage. The fourth exemplary embodimentmay further include a fiber buffer 410. Although the fourth exemplaryembodiment is shown with a lensed tip 406, the invention may bepracticed with other types of tips including flat tip 414, or any othertype of tip as determined by at least an optical source, an opticalfiber, an optical package, an application or any combination therein.

Although the first through fourth exemplary embodiments do notillustrate coating covering a portion of fiber tip 406 or 414, it is tobe understood that a coating may extend up to a fiber tip.

Although FIGS. 4 a-e illustrate some sample shapes, it is contemplatedthat the any shape may be provided to remove the coating and allow theescapement of absorbed non-confined light.

The type of pattern and placement on a fiber end may depend at leastupon the type of application, NA of a fiber core, optical source powerand optical package and attachment points within an optical package.Thus, the exemplary embodiments of the present invention may provideflexibility in developing an optical fiber to optical package attachmentwith reduced fiber damage at higher powers or brightness situationssuitable for a particular application.

Referring now to FIG. 5, an exemplary method of post-processing anoptical fiber to provide an exemplary optical fiber end according to thepresent invention is described. In step 500, a common in the art coatedfiber end may be positioned in an optical package according to at leastan optical source and optical package. In step 502, the coated opticalfiber end may be attached with solder at least where coating is disposedon the optical fiber end for precisely aligning the fiber end with anoptical source.

In step 504, an aperture based pattern is removed from the attachedoptical fiber according to an embodiment of the present invention. Alaser may desirably ablate portions of the coating to expose barecladding according to exemplary aperture patterns as described above toprovide, in step 506, a finished aperture patterned coated optical fiberaccording to an embodiment of the present invention. It is contemplatedthat chemical or mechanical means may be provided to remove portions ofthe coating.

The exemplary method of post-processing an optical fiber as describedabove provides advantages over usage of a common in the art opticalfiber. A common in the art coated optical fiber may be attached asdesired for at least a particular application, optical package andoptical source without requiring a specialized selection of an opticalfiber. After the optical fiber is attached, a laser may remove portionsof the coating dependent on at least the particular optical source andapplication. Thus, a special fiber dependent on at least the opticalpackage and optical source is not required. Further, an aperturepatterned coated optical fiber may further reduce the risk of absorbednon-confined optical power creating hot spots and potentially damagingthe optical fiber. Thus, the life of the optical fiber and the device towhich the optical fiber is attached may be extended.

Although not shown, it is to be understood that an aperture patternedcoating may be applied during optical fiber manufacture, according to anembodiment of the present invention after a coating is applied to theoptical fiber. Thus, according to optical fiber manufacturing, a coremay be provided and a cladding may be formed around the core. A coatingmay be applied to at least a portion of the cladding at an end of theoptical fiber. A laser may then remove portions of the coating accordingto an embodiment of the present invention. Thus, an aperture patternedcoating may be formed in the optical fiber manufacturing process aftercoating is applied. It is contemplated that chemical or mechanical meansmay be provided to remove portions of the coating.

Referring now to FIG. 6, an exemplary method of manufacturing anexemplary optical fiber according to the present invention is nowdescribed. In step 600 an optical fiber core having a refractive indexmay be provided by common in the art methods. In step 602, a claddingmay be formed around the cladding by common in the art methods. Thecladding may have a refractive index less than the refractive index ofthe core.

In step 604, an aperture patterned mask is desirably applied around thecladding of at least a portion of a fiber end. A patterned mask may bewrapped around the cladding. The aperture patterned mask may be providedas described above according to exemplary embodiments of the presentinvention.

In step 606, a coating is desirably applied to at least a portion of thecladding of the optical fiber end as described above to provide a coatedoptical fiber cladding end. In step 608, mask lift-off is performed,where the aperture patterned mask applied in step 604 is removed fromthe portion of the fiber end, thus providing the aperture patternedcoated fiber of step 610 and exposing the cladding through the aperturepatterns in the coating.

Referring now to FIG. 7, an alternate exemplary method of manufacturingan exemplary optical fiber according to the present invention is nowdescribed. In step 700, an optical fiber core having a refractive indexmay be provided. In step 702, a cladding may be formed around thecladding. The cladding may have a refractive index less than therefractive index of the core. In step 704, a coating is desirablyapplied to at least a portion of the cladding at an optical fiber end asdescribed above to provide a coating of an optical fiber end.

In step 706, a photoresist is applied to the coating. In step 708, thephotoresist is desirably exposed to at least a portion of radiationaccording to an aperture patterned mask as described in the exemplaryembodiments of the present invention. In step 710, the unexposedphotoresist may be removed. In step 712, coating exposed from under theremoved unexposed photoresist may be etched. In step 714, exposedphotoresist is removed to expose the coating, thus providing theaperture patterned coated fiber of step 716.

As described above in the exemplary methods of manufacture, an aperturepatterned coated optical fiber may be manufactured by: a) pre-maskingthe optical cladding, b) chemical processing of the optical fiber usingan aperture patterned masked radiation or c) remove portions of thecoating after the coating is applied to provide an aperture patternedcoating. Alternatively, post-processing of a common in the art coatedfiber may be provided after the optical fiber is attached to an opticalpackage by laser ablating the coating to form an aperture patternedcoating.

Although the invention is illustrated and described herein withreference to specific embodiments, the invention is not intended to belimited to the details shown. Rather, various modifications may be madein the details within the scope and range of equivalents of the claimsand without departing from the invention.

1. A method of processing an optical fiber comprising a core having arefractive index, a cladding surrounding the core having an index ofrefraction less than the index of refraction of the core and a coatingon the surface of a segment of the cladding, the segment being proximateto an end of the optical fiber, the method comprising the steps of:defining at least one location on the coating in which to providepatterned apertures in the coating; and selectively removing portions ofthe coating to provide the patterned apertures in the coating at thedefined at least one location.
 2. The method according to claim 1,wherein the step of selectively removing portions of the coating furthercomprises processing the coating with one of a laser, chemical means andmechanical means to selectively remove portions of the coating at thedefined at least one location.
 3. The method according to claim 1,wherein the step of selectively removing portions of the coating furthercomprises the steps of: attaching a portion of the segment proximate tothe end of the optical fiber to an optical package; and processing thecoating with a laser to selectively ablate portions of the coating atthe defined at least one location.
 4. The method according to claim 1,wherein the step of processing the coating provides at least onecircumferential groove as the patterned apertures.
 5. The methodaccording to claim 1, wherein the step of processing the coatingprovides patterned apertures that are polygonal shaped.
 6. A method ofmanufacturing an optical fiber, the method comprising the steps:providing a core having a refractive index; forming a claddingsurrounding the core having an index of refraction less than the indexof refraction of the core; forming an aperture patterned coating on asurface of a segment of the cladding proximate an end of the opticalfiber.
 7. The method according to claim 6, the step of applying theaperture patterned coating further comprising the steps of: forming acoating on at least a portion of the surface of the segment of thecladding; and processing the coating to provide patterned apertures intile coating, the patterned apertures providing the aperture patternedcoating.
 8. The method according to claim 6, the step of applying theaperture patterned coating further comprising the steps of: forming acoating on at least a portion of the surface of the segment of thecladding; applying a photoresist to the coating; exposing a portion ofthe photoresist to radiation to provide an unexposed portion of thephotoresist; removing unexposed portions of photoresist to expose aportion of the coating; etching the exposed coating to form patternedapertures in the coating, the patterned apertures providing the aperturepatterned coating; and removing an exposed photoresist to expose thecoating.
 9. The method according to claim 6, the step of applying theaperture patterned coating further comprising the steps of: forming amask on the surface of the segment of the cladding, the mask providingpatterned apertures; forming a coating onto the surface of the maskedsegment of the cladding; and removing the mask on the cladding toprovide patterned apertures in the coating, the patterned aperturesproviding the aperture patterned coating.
 10. The method according toclaim 6, wherein the step of applying the aperture patterned coatingprovides patterned apertures formed of at least one circumferentialgroove.
 11. The method according to claim 6, wherein the step ofapplying the aperture patterned coating provides patterned aperturesthat are polygonal shaped.